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Boric and boronic acids were used as inhibitors of beta-lactamases produced by two Citrobacter diversus strains and by one strain of Pseudomonas aeruginosa; all strains were clinical isolates. The beta-lactamases produced by the two Citrobacter diversus strains were inhibited by both borates and boronates, using cephazolin as substrate. The enzyme from Pseudomonas aeruginosa was inhibited only by boronates, using benzylpenicillin as substrate. These inhibitors were also used in combination with selected beta-lactams so as to determine if a synergism of antimicrobial activity occurred. All data reported in the present paper indicate that the minimum inhibitory concentration (MIC) values were lowered in the presence of these inhibitors for the two Citrobacter diversus strains. In the Pseudomonas aeruginosa strains the MIC values were not significantly altered, thus indicating the presence of a permeability barrier for 3-aminophenylboronic acid.

Leukotrienes are naturally-occurring metabolites of arachidonic acid that are formed via the 5-lipoxygenase pathway in several tissues. Rat peritoneal cells (RPC) can produce leukotrienes C4, D4 and E4 (LTC4, LTD4 and LTE4) in response to stimulation with the calcium ionophore A23187 (1,2). The mechanism of enzymatic conversion of LTC4 to LTD4 is presumed to be via the action of gamma-glutamyl transpeptidase (gamma-GTPase, Figure 1) and has been demonstrated with purified enzymes from rat and porcine kidneys (3-6). We report that RPC contain gamma-GTPase-like activity that catalyzes the liberation of p-Nitroaniline (p-NA) from the chromophoric substrate gamma-glutamyl-p-nitroanilide (gamma-GpNA) in the presence of the acceptor molecules glycylglycine and L-cysteine. Furthermore, we demonstrate that under similar conditions, this preparation catalyzes the conversion of LTC4 to LTD4. Activity with gamma-GpNA is inhibited by D,L-gamma-glutamyl(o-carboxy)-phenylhydrazide (GOP) and serine-borate complex, (competitive inhibitors of kidney gamma-GTPase), and 6-diazo-5-oxo-L-norleucine (DON) and o-diazo-acetyl-L-serine (AZA), (irreversible inhibitors of kidney gamma-GTPase). In contrast, conversion of both endogenously-generated or exogenous LTC4 into LTD4 by RPC is inhibited only by serine-borate complex. These results suggest that RPC contain at least two distinct forms of gamma-GTPase; one capable of recognizing gamma-GpNA and susceptible to inhibition by all four compounds, and a second form utilizing also LTC4 as substrate, and is not inhibited by high concentrations of several "classic" gamma-GTPase inhibitors.

Reversible competitive inhibitors of a penicillinase, beta-lactamase 1 from Bacillus cereus, were studied. These represent the first inhibitors of a penicillinase that lack the beta-lactam ring. The products of the enzymic reaction, namely penicilloic acids, are inhibitors; their decarboxylation products, the penilloic acids, are also inhibitors, and have somewhat lower Ki values. Inhibitors have been prepared from benzylpenicillin, phenoxymethyl-penicillin, methicillin (2,6-dimethoxybenzamidopenicillanic acid) and 3-hydroxy-4-nitrobenzamidopenicillanic acid. Decarboxylation of the penicilloic acids from benzyl-penicillin, or from phenoxymethylpenicillin, leads to epimerization (at C-5) of the penilloic acid. Nuclear-magnetic resonance spectroscopy at a frequency of 270 MHz can distinguish the epimers. Other competitive inhibitors studied were boric acid, benzene boronic acid and m-aminobenzeneboronic acid. Boric acid itself was the best inhibitor of beta-lactamase I so far found.

The authors compared the action of boric, benzene-boronic and p-methyl-benzene-boronic acids on respiration and general metabolism and on systemic hemodynamics of the anesthetized dog. They further investigated the effects on the arterial blood pressure in the rat and on the isolated rabbit heart. In the dogs, the three acids were shown to have no significant action on the systolic, diastolic and mean arterial blood pressures and a slight stimulating action on the differential arterial blood pressure. On the contrary, in the rat, all the acids were hypotensive. This action was dose dependent. In the entire animal, as well as in the isolated rabbit heart, benzene-boronic and p-methyl-benzene-boronic acids depressed the myocardial contractility. Whereas boric acid did not act on the heart contractility in situ in anesthetized dogs, it slightly stimulated the myocardial contractility of the isolated rabbit heart. The two acids seemed to be directly active on the myocardial cell. In the anesthetized dog, cardiac performances were first depressed then stimulated. Both benzene-boronic and p-methyl-benzene-boronic acids were ventilatory depressors: they reduced ventilatory output and rhythm, they first decreased then increased total O2 consumption and CO2 production.

The effect of borogluconate on plasma calcium fractions was studied in vitro and in vivo in sheep. In vitro calcium chloride was more effective in raising ionised plasma calcium than calcium borogluconate. Sodium borate or gluconate added to blood caused only small decreases in blood ionised calcium. However, together, a synergistic reduction in ionised calcium was observed. Following calcium borogluconate infusions into sheep, total plasma calcium rose primarily because of an increase in the unionised ultrafiltrable fraction. Other changes observed following the infusion were hypercalciuria, decreased glomerular filtration rate and acidosis. Sodium borogluconate administered subcutaneously lowered total plasma calcium. This probably resulted from enhanced calcium excretion. It is suggested that since the anionic component of calcium solutions alters the availability and retention of calcium, it is likely to affect clinical efficacy significantly.

Colchicine, boric acid, and camphor were used to produce viable cultures of Trichothecium roseum actively producing the antibiotic, by treating the submerged vegetative mycelium of the fungus with these compounds. Colchicine (0.5--1.0%), boric acid (0.25--2.00%), and camphor (0.25--1.50%) were added to the nutrient medium before it was inoculated with conidia or vegetative mycelium; later, the submerged mycelium was transferred to slanted agar. The cultures were characterized by a high number of the nuclei in the conidia, a low ratio of the plasma to the nuclei, a high rate of growth, and a high antibiotic activity. In sharply varying conditions of nutrition, such polynuclear forms had an adaptive advantage as compared to the parent forms. The polynuclear cultures are regarded to be biologically equal to polyploid forms.

A simple method which allows rapid, reproducible biotyping of Candida albicans isolates, and is suitable for use in any diagnostic medical microbiology laboratory is described. This system comprises three tests, the API ZYM system, the API 20C system, and a plate test for resistance to boric acid. The system differentiated a possible 234 biotypes, of which 33 were found amongst the 130 isolates of C. albicans taken from oral, genital and skin sites. Major biotypes found amongst oral and non-oral isolates were similar, although differences were found amongst minor biotypes. The new system was found to be reproducible, discriminatory, reasonably fast (48 h), easy to perform, and had no requirement for specialised equipment. Hence this biotyping system is suitable for use in diagnostic microbiology laboratories for epidemiological investigations of C. albicans infections.

Boric acid in a dose of 1 g/kg was given orally to albino rats for a period of 2 weeks, daily. Changes in the nucleus and the cytoplasm of both the spermatozoids and spermatides were revealed at the early stages of their formation. The appearance of numerous multinuclear cells with an even and odd number of nuclei (from 2 to 10 and over) was noted. The formation of multinuclear cells can be apparently attributed to the action of boric acid on the prolonged processes of meiotic division of the spermatogenic epithelium cells (spermatocytes, spermatides).

Stable bacterial counts in urine specimens before culture are necessary to assure the accurate diagnosis of urinary tract infections. Preservative-containing tubes are commercially available for urine transport. As these tube containers are not always filled to the manufacturer's specifications, we studied the effects of stabilizer formation with low urine volumes. The Sage Urine Culture Tube and the Becton-Dickinson Urine Culture Kit were evaluated by using 30 cultures diluted in urine to 10(5) colony-forming units per ml. Both tube types were injected with 1, 2, 3, and 4 to 5 ml (tube capacity) of urine containing each culture. Specimens were held at 22 degrees C and cultured at 0, 4, and 24 h. Colony counts were corrected for the dilution due to the preservative. The Becton-Dickinson Urine Culture Kits were toxic to Escherichia coli and Klebsiella pneumoniae in specimens containing up to 2 ml of urine, and the minimum usable amount of urine for reliable results was 3 ml. The Sage Urine Culture Tube maintained the number of bacteria in 1 to 4.5 ml of urine in 83% of the specimens. However, the Sage tube was toxic to E. coli when held for 24 h. Quantitative counts of enterococci tended to significantly increase in specimens that contained 2 ml or more of urine with either system. The limitation of preservative-containing tubes for urine transport need to be recognized in order to avoid false-positive and false-negative results.

The effect of lysosomotrophic agents and primary amine inhibitors of transglutaminase on Shigella toxin activity in HeLa cells was determined by measuring cytotoxicity and late antibody rescue. All agents tested resulted in significant antibody rescue, but only ammonium chloride, dansylcadaverine, putrescine, bacitracin, serine/borate buffer, and chloroquine were inhibitory in the absence of added antibody. These compounds appear to be acting within the endocytic vacuole and/or inhibiting translocation of toxin from the cell surface to the cytosol. These data are consistent with a mechanism of translocation of ST from the cell surface to the cytosol by the process of receptor mediated endocytosis.

Urease was purified 800-fold and partially characterized from Proteus mirabilis, the predominant microorganism associated with urinary stones. Boric acid is a rapid reversible competitive inhibitor of urease. The pH-dependence of inhibition exhibited pKa values of 6.25 and 9.3, where the latter value is probably due to the inherent pKa of boric acid. Three boronic acids also were shown to inhibit urease competitively.

The effect of colchicine and boric acid on the substrate mycelium of Trichothecium roseum was studied in the course of trichothecin biosynthesis. Addition of boric aicd (0.01%) and colchicine (0.1%) to the medium for biosynthesis increased the antibiotic activity of the fungus, this being due to the specific effect of polyploidogenous factors on growth of the mycelium and the proportion of nuclei in it. The number of nuclei increased in cells of the substrate mycelium correlating with a higher antibiotic activity.

Glutaminase B is both activated and inhibited by L-glutamate, the product of the reaction. The activation process is time- and temperature-dependent. Activation by L-glutamate alters the Vmax, So.5, and shape of the substrate saturation curve. The activation decays as a first order process with time after separation of L-glutamate from glutaminase B. L-Glutamate inhibits both glutaminase B and the glutamate-activated enzyme. Like L-glutamate, borate activates and inhibits glutaminase B. Inhibition of the enzyme by glutamine and glutamate analogs is also examined and similarities between the glutamate activation and activation by warming at 23 degrees are noted.

This study evaluated the in vitro virucidal activity of soluble components of a topical film-forming medication, Zilactin, against Herpes simplex virus type 1 (HSV-1). Using a standard plaque reduction assay, a 1:10 dilution of the experimental liquid resulted in total destruction of infectious HSV-1. The phenomenon could not be explained by ethanol concentration or lowering of pH, both of which had no effect on control samples. As employed in this assay, Zilactin diluted 1:10 did not demonstrate cyctotoxicity to the cell monolayer system. The implications of these findings on the design and implementation of clinical trials are discussed, with special reference made to the restrictions imposed by the natural history of clinical lesions caused by HSV-1.

In order to study the in vitro behavior of the drug used according to our formula cultures of Trichophyton mentagrophytes. Trichophyton rubrum, Trichophyton verrucosum, Trichophyton tonsurans, Microsporum canis, Microsporum gallinae, Microsporum audouinii, Microsporum gypseum and Epidermophyton floccosum were prepared in order to prove its efficacy. It was found no growth in cultures to which the drug was added in different concentrations thus proving its efficacy as a fungistatic element. The inocula obtained were re-cultured in the same medium having no drug and no growth was evidenced; this would suggest its efficacy as a fungicide. This efficacy was proved for the different concentrations, that is, from the minimal coinentration (0.1 ml) up to the 1 ml concentration the drug disclosed fungicide power. The untreated controls which were recultured from the original strains grew according to their common development rhythm.

The tests commonly used for bacterial identification, especially in the field of microbial environmental analyses frequently do not provide a sufficient strain differentiation. Considering the importance that accurate characterization of bacterial pollution indicators could have as epidemiological tools, this study used a resistogram subtyping method for Escherichia coli as a tentative method of effecting a good monitoring of the environmental spread of this microorganism. The resistance of 313 E. coli strains of different origin (human, animal, sewage), previously identified by standard biochemical reactions, to 8 chemical compounds (inorganic, organic and dyes) and to 7 antibiotics was tested. The results indicated this method has a higher discriminatory power for chemicals than for drugs. Some typical resistotype patterns for E. coli from various sources are described.

A study was made of the activation of Bacillus cereus strain T spores by using the oxidizing agent sodium perborate. The degree of activation was measured with constant germination conditions by using L-alanine, inosine, adenosine, and L-alanine plus adenosine as germination stimulants. The germinal response following the various treatments was compared with the responses obtained with heat activation. It was concluded that the optimal time for activation with 30 mM sodium perborate at room temperature was about 4 hr. If the exposure time was greatly extended, the spores would germinate spontaneously. When the perborate treatment followed heat activation, the germinal response to L-alanine was stimulated, to inosine retarded and without apparent effect for adenosine or L-alanine plus adenosine. Results of experiments designed to demonstrate deactivation by slow oxidation showed that spores activated with sodium perborate were not deactivated by slow oxidation, whereas those activated by heat were. A deactivation study using mercaptoethanol as the deactivation agent showed that both methods of activation could be deactivated after a 24-hr exposure, but this deactivation was reversible by extending the exposure to mercaptoethanol. The results of heat-sensitivity studies revealed that about 70% of the sodium perborate-activated spores were heat sensitive after 60 min in a germination menstruum of L-alanine plus adenosine, whereas similarly treated heat-activated and nonactivated spores were about 99.99% heat sensitive, respectively.